What is Down syndrome?
A genitic condition that causes delays in physical and intellectual development
incidence of down syndrome?
one in every 700 live births, most frequently occuring chromosomal disorder. NOT related to race, religion or socioeconomic status.
Cause of Down Syndrome?
an error in cell division called nondisjunction. occurs at conception and is not related to anything the mother did during pregnancy.
What increases the incidence of Down Syndrome?
advanced maternal age but 80% of children born to women under 35 yrs old.
What is different about the chromosomes of individuals with Down Syndrome?
They have 47 chromosomes instead of 46.
3 chromosomal patterns that result in Down Syndrome and which is the most common?
- trisomy 21 (nondisjunction) - MOST common (95%)
- translocation (3-4%)
- mosaicism (1-2%)
What is trisomy 21 caused by?
a faulty cell division that resluts in the baby having three #21 chromosomes instead of two. Prior or at conception, a pair of #21 chromosomes in either the egg or the sperm fails to separate properly. The extra chromosome is replicated in every cell of the body.
What is translocation caused by?
part of chromosome #21 breaks off during cell division and attaches to another choromosome. The presence of an exra piece of the 21st chromosome causes the characteristics of down syndrome. May indicate that one of the parents is carrying chromosomal material that is arranged in an unusual manner.
What is mosaicism cause by?
Occurs when nondisjunction of chromosome #21 takes place in one of the initial cell divisions after fertilization. when this happens, there is a mixture of two types of cells, some containing 46 chromosomes and some with 47. because of the mosaic pattern of the cells, the term mosaicism is used.
When is Down Syndrome diagnosed?
- before or at birth. Before birth, ultrasound 10-14 weeks gestation - thick neck (nuchal translucency)
- initially the diagnosis is based on physical characteristics.
- The diagnosis must be confirmed by a chromosome study (karyotype)
Common physical features of Down Syndrome?
- Flattened nasal bridge
- almond shaped eyes
- flat occiput
- short limbs, short broad hands and feet
- high arched palate - protruding tongue
- muscle hypotonia
- jt hyperextensibility
- simian line (transverse palmer crease)
Common medical manifestations of Down Syndrome?
- hypothyroidism (8%) require medication
- heart disease: (50%) defects may require medication or surgery
- increased incidence of childhood leukemia (1%) and incidence of colds and infections.
Secondary medical manifestations (after age 30-35) of Down Syndrome?
obesity, diabetes, CVD, osteoarthritis, orstoporosis.
by age 40 almost everyone with Down Syndrome will have symptoms of alzheimers.
Common orthopedic impairments of peopl with Down Syndrome?
excessive foot pronation, scoliosis, slipped capital femoral epiphyses (hip abduction with hypotonia), late hip dislocation (after age 2), patellofemoral disroders (patellar dislocation), atlantoaxial (C1-C2) instability.
vision impairments of patients with Down Syndrome?
35-60% have affected vision. Near or far sighted, esotropia (cross eyed) and/or cataracts. May require surgery or glasses.
Hearing impairments of patients with Down Syndrome?
66-89% have hearing impairments. Ear (internal and external) deformities may lead to hearing loss. Regular hearing exams recommended.
Cognitive, communication, and learning impairments of people with Down Syndrome?
"intellectually imapired" can be mild to severe. Learning disabilities may be present requiring special education. Receptive and expressive language may be delayed requiring speech therapy, augmentative communication, and/or sign language.
Gross motor and mobility skills of people with Down Syndrome?
delayed due to low muscle tone, loose ligaments, and decrease strength. Walking usually occurs around age 2. Gross motor development continues throughout the lifespan, yet it remains delayed. Increased incidence of overweight with age may affect fitness level.
Gross motor clinical obsercations of patients with Down Syndrome?
Poor upper extremity midline movements, slow reaction time, and slower postural reaction times.
Gait of people with Down Syndrome?
Short steps, wide base of support, increased knee flexion in swing, increased knee flexion in swing and hyperextension in stance, Decreased single limb support.
Prognosis and outcomes of patients with Down Syndrome?
Life expectancy is approximately 55 years. Education and work training available, allowing great opportunity for productivity: many go on to college, have jobs, and live independently.
What is atlantoaxial (C1-C2) instability?
- Subluxation between C1 and C2. Most cases are asymptomatic. Cervical subluxation greater than 4.5 mm is an indicator for intervention (surgical).
- Secondary to ligamentous laxity or poor development of the odontoid or abnormal syringomyelia.
Upper cervical spine instability signs and symptoms?
hyperreflexia, clonus, positive babinski's sign, loss of strength, changes in senstion, torticollis, loss of established bowel and bladder control, derease or loss of established motor skills.
Complications of arthrodesis?
bone graft reabsorption, wound dehiscence and infection, instability of adjacent motion segment, incomplete reduction of C1-C2, neurologic sequelae.
What is the AA debate about?
age for x-rays to identify AAI, reliability of x-ray results to identify AAI, surgical intervention.
What do people need in order to participate in special olympics?
They need to be medically cleared for AAI. Need to communicate with local orthopedic surgeon.
What activities should people with Down Syndrome avoid?
Direct downward forces such as tumbling, diving, horse back riding, carnival rides, driving on poorly maintained road.
What is PT treatment focused around?
There is no cure, treatment is focused on specific impairments. PT cannot change muscle tone.